Design of a variable displacement gear pump

Diplomski rad bavi se analizom postojećih rješenja pumpi s promjenjivim specifičnim protokom. U radu su opisane različite vrste pumpi, a detaljnije zupčaste pumpe s vanjskim ozubljenjem i promjenjivim specifičnim protokom. Analizom postojećih komercijalnih rješenja konstruirana je osnovna pumpa bez mogućnosti promjene specifičnog protoka. Na temelju navedene pumpe konstruirano je nekoliko pumpi koje omogućavaju promjenu specifiĉnog protoka. Upravljanje protokom dobiva se pomoću dva različita principa. Prvi je prigušenje, odnosno direktno spajanje tlačne s usisnom stranom, dok je drugi promjena volumena radnog fluida u zahvatu na tlačnoj strani pumpe.The thesis deals with the analysis of existing pumps with variable displacement. Various types of pump constructions are described and more detalied external gear pumps with variable displacement. A basic pump without the possibility of variable displacement is designed by analizing existing commercial solutions. Several pumps have been designed which allow variable displacement and are based on the basic pump model. Displacement change is obtained through two principles. The first is damping, or direct connection of pressure and suction chambers, while the second is changing of the pump displacement volume in the pumps pressure chamber